n,k = map(int,input().split())
*a, = map(int,input().split())
a.sort()
MOD = 10**9+7
idx = 0
ans = 1
for i in range(n//2):
    while idx < n and a[n-1-i] + a[idx] <= k:
        idx += 1
    ans *= min(idx-i,n-1-i*2)
    ans %= MOD
print(ans)